function Popup() {
  this._bg = null;
  
  this._createElements();
}

Popup.prototype._createElements = function() {
  var _self = this;
  
  var size = DOMUtils.xDocSize();
  this._bg = document.createElement('div');
  this._bg.style.backgroundImage = 'url(templates/ui/default/assets/bw.png)';
  this._bg.style.backgroundRepeat = 'repeat';
  this._bg.style.width = size.w - 20 + 'px';
  this._bg.style.height = size.h - 20 + 'px';
  this._bg.style.position = 'absolute';
  this._bg.style.display = 'block';
  this._bg.style.top = '0px';
  this._bg.style.left = '0px';
  document.body.appendChild(this._bg);
};

Popup.prototype._close = function() {
  if (this._bg) {
    document.body.removeChild(this._bg);
    this._bg = null;
    this._pane = null;
  }
}
